Cold showers?

I have a 7 zone radiant heating system run by 2 boilers. There is a setup for a wood boiler outside as well but not hooked up. There is a big blue hot water holding tank as well.

House seems to heat fine. (just bought the house this last winter).

If only one person is taking a shower the hot water is fine. If there is someone running hot water at the same time or 2 showers going at the same time I can only get luke warm water. This is luke warm at the sink as well. Once you turn the other shower off the water slowly warms up again. The water in the tank is staying at a constant 125ish and does not fall during this time. I don't know much about these systems. The plumber that installed the second boiler for the bank just before we bought it seems to think there is a scald protector somewhere in the system that may be bad. I don't have alot of confidence it this guy though. Anyone know what this is?

Also I said that my expansion tank had a hole in the bladder. He wanted to put a new one in for $360. I see online that these are only a $50 item and don't look all that hard to change so I figured I may tackle that myself. I expected when I got home to find that the expansion tank would be full of water like he said but it seems like it is empty. How do I check this?

Comments

It is certainly possible you have a malfunctioning mixing valve. Mixing valves are not all that common in homes and would not normally be concealed. I suspect you have a cross connect between the hot and cold somewhere in the house. I would look around for odd plumbing connections under sinks ect. A common one is hot and cold hose connectors with "Y" hoses on them. I would start turning off the valves in suspect areas and try to eliminate the problem.

Expansion tanks would normally be around half full of water. You should be able to tap on the side and tell if they are bad. You can use a bike pump on the bottom and attempt to re pressurize. If the bladder is blown you will have to replace it.

You are certain the tank is heating to 120 right?

"If you can't explain it simply, you don't understand it well enough"Albert Einstein

Ya. And the water is really hot out of the tap as long as there is not too much load. Once you have more than one shower going the water is luke warm at best the but tank holds at the same temp regardless. I should probably take pictures.. maybe that would help. there is a valve that has a dial on it. Is that the mixing valve?

The tank really doesn't seem to have any water in it at all when I try and shake it (difficult to do when connected to pipe). Maybe it is full.. I'm not really that sure of myself. Anyone know someone trustworthy in SW Michigan that may be able to look things over?

You have a simple problem that is far too complicated for a quick answer here. There are too many paths to go down to find your problem. Most of us are not "Trial & Error" mechanics. in other words, we do not change parts until the problem goes away.

Your "plumber" may be good at putting pipes together but his troubleshooting skills need some work. For example, what you describe as a "tank" seems to be a bladder tank. And not a hydro-pneumatic expansion tank. With "Extrol" type bladder tanks, the only way I could truly tell if the bladder had failed and the tank was full of water was not by tapping it on the side, but unscrewing it from the fitting and having a 50#+ object crash to the floor, demolishing anything in the way. That is why I always tie a bucket to the fitting and let the tank fall a few inches into the bucket rather than a few feet of vertical drop.

A very experienced professional here was faced with a similar problem which was stumping him. He asked for help here. He found it and found the problem. You have a similar problem. Your "plumber" seems to be clueless as to the problem and may be clueless as to how to check a bladder tank.

I suggest you get out your wallet and find someone that is a little more experienced than you and your "plumber".

I could personally find your problem in less than 10 minutes. I've done that after multiple "others" haven't found it. It's kind of like knowing how grass grows. Simple but complicated.

He could also have an Amtrol indirect DHW tank that has a coil leak, as well as an expansion tank issue. There should be 2 expansion tanks...one for the boiler system and a potable expansion tank for the indirect.

I would love to pay someone I trusted to do this. I don't think this guy knows what he is doing and don't trust him to make further repairs. The people that originally installed the system are gone. The only reason I contacted this guy is because he put in the second boiler for the bank ($17k). (the original owner has no idea why he would do this since it has heated well for 5 years.) If someone knows anyone in SW michigan that would be great. The closest I can find is Holland but that is one hour away.

That alone tells me someone has no clue as to what they are doing. may I ask what type of boilers these are as well as the btu/hr rating on them? Take pics and post them it will help all to at least point you in the right direction.

"The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."

in houses that have driven me nuts. Getting out of the mechanical room for a bit and something you can do and save yourself some dough is to do isolation runs with the hot water. Washing machines can cross flow. Shut off the valve and run your hot water tests. Every fixture has a hot and a cold. turn off the colds and see how the hot runs. Bring on the colds sequentially and see if it makes a difference. Do you have tempering valves on your toilets? In order to eliminate condensation on the toilets people have installed tempering valves that put warm water into the toilet. They can definitely back-flow and have produced exactly the type situation you are talking about.

I didn't realize that the ergomax WAS a reverse indirect. That being the case. if the temp gauge is reading 125 deg. The boiler supply temp needs to be turned up and a mixing valve installed (if not already present). 125 is way to low for a reverse indirect.

You need to turn the Ergomax up to 180 deg. to optimize performance (and install a mixing valve for safety). It looks like you have a nice yet very complex (and over-pumped) system. Hopefully someone here can recommend a pro in your area, if not, try contacting NTI or their local rep to get a pro to come in and set the system up correctly. Keep us posted.

P.S. Start the Ergomax at 180 deg. Then run the amount of fixtures that you would normally run at any given time. you can then lower the Ergomax temperature until domestic water temp starts dropping, once that happens, turn the Ergomax up 5 degree's and it is set for your standard usage. A mixing valve MUST be installed for standard use of this unit. You can do the temperature adjustments as descibed above without it, but for actual use you have to have a mixing valve for anti-scald protection. (any plumber should be able to install the mixing valve).